The progressive mob that disrupted Charles Murray's appearance last week at Middlebury College was protesting a 1994 book read by few if any of the protesters. Some of them denounced "eugenics," thereby demonstrating an interesting ignorance: Eugenics -- controlled breeding to improve the heritable traits of human beings -- was a progressive cause.

In "The Bell Curve," Murray, a social scientist at the American Enterprise Institute, and his co-author, Harvard psychologist Richard J. Herrnstein, found worrisome evidence that American society was becoming "cognitively stratified," with an increasingly affluent cognitive elite and "a deteriorating quality of life for people at the bottom end of the cognitive ability distribution."

They examined the consensus that, controlling for socioeconomic status and possible IQ test bias, cognitive ability is somewhat heritable, that the black/white differential had narrowed, and that millions of blacks have higher IQs than millions of whites.

The authors were "resolutely agnostic" concerning the roles of genes and the social environment. They said that even if there developed unequivocal evidence that genetics are "part of the story," there would be "no reason to treat individuals differently" or to permit government regulation of procreation.

Middlebury's mob was probably as ignorant of this as of the following: Between 1875 and 1925, when eugenics had many advocates, not all advocates were progressives but advocates were disproportionately progressives because eugenics coincided with progressivism's premises and agenda.

Progressives rejected the Founders' natural rights doctrine and conception of freedom. Progressives said freedom is not the natural capacity of individuals whose rights pre-exist government. Rather, freedom is something achieved, at different rates and to different degrees, by different races. Racialism was then seeking scientific validation, and Darwinian science had given rise to "social Darwinism" -- belief in the ascendance of the fittest in the ranking of races.

The progressive theologian Walter Rauschenbusch argued that with modern science "we can intelligently mold and guide the evolution in which we take part."

Progressivism's concept of freedom as something merely latent, and not equally latent, in human beings dictated rethinking the purpose and scope of government. Princeton University scholar Thomas C. Leonard, in his 2016 book "Illiberal Reformers: Race, Eugenics & American Economics in the Progressive Era," says progressives believed that scientific experts should be in society's saddle, determining the "human hierarchy" and appropriate social policies, including eugenics.

Economist Richard T. Ely, a founder of the American Economic Association and whose students at Johns Hopkins included Woodrow Wilson, said "God works through the state," which must be stern and not squeamish. Charles Van Hise, president of the University of Wisconsin, epicenter of intellectual progressivism, said: "We know enough about eugenics so that if that knowledge were applied, the defective classes would disappear within a generation."

Progress, said Ely, then at Wisconsin, depended on recognizing "that there are certain human beings who are absolutely unfit, and who should be prevented from a continuation of their kind." The mentally and physically disabled were deemed "defectives."

In 1902, when Wilson became Princeton's president, the final volume of his "A History of the American People" contrasted "the sturdy stocks of the north of Europe" with southern and eastern Europeans who had "neither skill nor energy nor any initiative of quick intelligence." In 1907, Indiana became the first of more than 30 states to enact forcible sterilization laws.

In 1911, now-Gov. Wilson signed New Jersey's, which applied to "the hopelessly defective and criminal classes." In 1927, the U.S. Supreme Court upheld Virginia's law, with Justice Oliver Wendell Holmes saying that in affirming the law requiring the sterilization of "imbeciles" he was "getting near to the first principle of real reform."

At the urging of Robert Yerkes, president of the American Psychological Association, during World War I the Army did intelligence testing of conscripts so that the nation could inventory its human stock as it does livestock. The Army's findings influenced Congress' postwar immigration restrictions and national quotas. Carl Brigham, a Princeton psychologist, said the Army's data demonstrated "the intellectual superiority of our Nordic group over the Mediterranean, Alpine and Negro groups."

Progressives derided the Founders as unscientific for deriving natural rights from what progressives considered the fiction of a fixed human nature. But they asserted that races had fixed and importantly different natures calling for different social policies.

Progressives resolved this contradiction when, like most Americans, they eschewed racialism -- the belief that the races are tidily distinct, each created independent of all others, each with fixed traits and capacities.